Coil component

Abstract

To provide a coil component which does not need ground connection and attains shield effect.SOLUTION: A coil component according to one embodiment includes: a magnetic base having magnetism; a conductor provided at a part of the magnetic base; an input side electrode provided on an outer surface of the magnetic base and connected to one end at the input side of the conductor; an output side electrode provided on the outer surface of the magnetic base and connected to one end at the output side of the conductor; and a conductive shield which is provided on the outer surface of the magnetic base and connected to the output side electrode of the input side electrode and the output side electrode and forms, with the output side electrode, a total area which is larger than an area of the input side electrode.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a coil component. [Background technology]

[0002] Coil components have a basic function of canceling out changes in current, and so have traditionally been used for noise suppression, filtering, etc. In recent years, power inductors have come to be used more and more as coil components, for example to smooth out AC current in DC-DC converters.

[0003] On the other hand, as the circuits in which coil components are used become higher in frequency, they can have an electromagnetic field effect (noise) on the electronic components surrounding the coil components.For this reason, it has been proposed to reduce electromagnetic field noise by providing a conductive shield to the coil components and connecting it to ground.

[0004] For example, Patent Document 1 discloses a coil component that includes a shield layer that is provided on the upper surface of an insulating body and has a higher magnetic permeability than the insulating body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2018-56505 A Summary of the Invention [Problem to be solved by the invention]

[0006] The coil component of Patent Document 1 requires a ground electrode for connecting the shield to ground in addition to the external electrode of the coil, and the board on which the coil component is mounted also requires a ground pattern connected to ground. However, the ground electrode prevents the coil component from being made smaller, and conversely, it is difficult to form a ground electrode on a miniaturized coil component.

[0007] In view of the above circumstances, an object of the present invention is to provide a coil component that does not require a ground connection and can obtain a shielding effect. [Means for solving the problem]

[0008] In order to solve the above problem, a coil component according to one aspect of the present invention comprises a magnetic base having magnetism, a conductor provided on a part of the magnetic base, an input side electrode provided on an outer surface of the magnetic base and connected to one end of an input side of the conductor, an output side electrode provided on the outer surface of the magnetic base and connected to one end of an output side of the conductor, and a conductive shield provided on the outer surface of the magnetic base, connected to the output side electrode of the input side electrode and output side electrode, and having a total area with the output side electrode larger than an area of ​​the input side electrode.

[0009] Furthermore, in a coil component according to one embodiment of the present invention, the magnetic base has a first surface on which the input electrode and the output electrode are provided, a second surface facing away from the first surface, and a side surface connecting the first surface and the second surface, and the shield has a second surface portion provided on the second surface and a side surface portion provided on the side surface.

[0010] In the coil component according to one aspect of the present invention, the area of ​​the second surface portion of the shield is larger than the total area of ​​the side surface portions. In the coil component according to one aspect of the present invention, the second surface portion of the shield covers 90% or more of the second surface.

[0011] In addition, in a coil component according to one aspect of the present invention, the shield has a protruding portion that is positioned outward from the second surface when viewed toward the second surface. In the coil component according to one aspect of the present invention, the second surface portion of the shield has a thickness equal to or smaller than a thickness of the output electrode.

[0012] In addition, in the coil component according to one aspect of the present invention, the shield contains a material having a higher resistance than the output electrode. In addition, in the coil component according to one aspect of the present invention, the shield is made of a non-magnetic metal.

[0013] In addition, in the coil component according to one aspect of the present invention, the input electrode and the output electrode are spaced apart from the side surface. Furthermore, the coil component according to one aspect of the present invention further includes markings for identifying the input side and the output side of the conductor. Effect of the Invention

[0014] According to the present invention, a shielding effect can be obtained without the need for a ground connection. [Brief description of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing a coil component according to a first embodiment of the present invention. [Diagram 2] 1 is a perspective view showing the top surface side of a coil component according to a first embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view showing the bottom surface side of the coil component according to the first embodiment of the present invention. [Figure 4] FIG. 11 is a cross-sectional view showing a coil component of a comparative example. [Diagram 5] FIG. 13 is a perspective view showing the top surface side of a coil component of a comparative example. [Figure 6] FIG. 13 is a perspective view showing the bottom side of a coil component of a comparative example. [Figure 7] 1 is a graph of the far electromagnetic field in an unshielded coil assembly. [Figure 8] 4 is a graph of a far electromagnetic field in the coil component of the first embodiment. [Figure 9] 1 is a graph of the far electromagnetic field when there is no connection between the shield and the external electrode. [Figure 10] FIG. 1 is a diagram illustrating a measurement environment of a near electromagnetic field. [Figure 11] 1 is a three-dimensional graph showing the near magnetic field in an unshielded coil component. [Figure 12]1 is a two-dimensional graph showing a near magnetic field in an unshielded coil component. [Figure 13] 4 is a three-dimensional graph showing a near magnetic field in the coil component of the first embodiment. [Figure 14] 4 is a two-dimensional graph showing a near magnetic field in the coil component of the first embodiment. [Figure 15] 1 is a three-dimensional graph showing the near-field of an unshielded coil component. [Figure 16] 1 is a two-dimensional graph showing the near-field of an unshielded coil component. [Figure 17] 4 is a three-dimensional graph showing a near electric field in the coil component of the first embodiment. [Figure 18] 4 is a two-dimensional graph showing a near electric field in the coil component of the first embodiment. [Figure 19] FIG. 6 is a cross-sectional view showing a coil component according to a second embodiment. [Figure 20] FIG. 11 is a perspective view showing the top surface side of a coil component according to a second embodiment. [Figure 21] FIG. 11 is a perspective view showing the bottom side of the coil component according to the second embodiment. [Figure 22] FIG. 11 is a cross-sectional view showing a coil component according to a third embodiment. [Diagram 23] FIG. 11 is a perspective view showing the top surface side of a coil component according to a third embodiment. [Figure 24] FIG. 11 is a perspective view showing the bottom surface side of the coil component according to the third embodiment. [Diagram 25] FIG. 11 is a cross-sectional view showing a coil component according to a fourth embodiment. [Figure 26] FIG. 13 is a perspective view showing an output side of a coil component according to a fourth embodiment. [Figure 27] FIG. 13 is a perspective view showing an input side of a coil component according to a fourth embodiment. [Figure 28] FIG. 13 is a cross-sectional view showing a coil component according to a fifth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the present invention, and not all of the combinations of features described in the embodiments are necessarily essential to the configuration of the present invention. The configuration of the embodiments may be appropriately modified or changed depending on the specifications of the device to which the present invention is applied and various conditions (such as usage conditions and usage environment).

[0017] The technical scope of the present invention is defined by the claims and is not limited by the following individual embodiments. The drawings used in the following description may differ in scale and shape from the actual structure in order to make each configuration easier to understand. The components shown in the drawings described above may be appropriately referenced in the description of the drawings that follow.

[0018] First Embodiment 1 to 3 are diagrams showing a coil device according to a first embodiment of the present invention, in which Fig. 1 shows a cross-sectional view, Fig. 2 shows a perspective view of the upper surface side, and Fig. 3 shows a perspective view of the lower surface side.

[0019] The coil component 110 is mounted on a substrate 120, and the circuit board 100 includes the coil component 110 and the substrate 120 on which the coil component 110 is mounted. The circuit board 100 is included in various electronic devices. Examples of electronic devices that include the circuit board 100 include electrical components for automobiles, servers, board computers, and various other electronic devices.

[0020] In this specification, unless otherwise understood in the context, the directions are described based on the "L axis" direction, the "W axis" direction, and the "H axis" direction shown in Figures 1 to 3, and are referred to as the "length" direction, the "width" direction, and the "height" direction, respectively. Note that the plane defined by the L axis and the W axis may be referred to as the LW plane, the plane defined by the L axis and the H axis may be referred to as the LH plane, and the plane defined by the W axis and the H axis may be referred to as the WH plane. The coil component 110 has an outer shape of a rectangular parallelepiped, for example. That is, the coil component 110 has outer surfaces at both ends in the length direction L, both ends in the height direction H, and both ends in the width direction W.

[0021] The dimensions of each side of the rectangular parallelepiped coil component 110 are, for example, 1.0 to 4.5 mm in the length direction L, 0.5 to 3.2 mm in the width direction W, and 0.5 to 1.0 mm in the height direction H. The dimension in the height direction H is smaller than the dimension in the length direction L, and further, the dimension in the height direction H is smaller than the dimension in the width direction W.

[0022] The outer surfaces of the coil component 110 may be flat or curved, and the eight corners and twelve edges of the coil component 110 may be rounded. In this specification, even when the outer surface of the coil component 110 is partially curved or when the corners or ridges of the coil component 110 are rounded, such a shape may be referred to as a "rectangular parallelepiped shape." In other words, in this specification, the term "rectangular parallelepiped" or "rectangular parallelepiped shape" does not mean a "rectangular parallelepiped" in the strict mathematical sense.

[0023] The substrate 120 is provided with, for example, two land portions 121 and 122. The coil component 110 has a magnetic base 111, an internal conductor 112, external electrodes 116 and 117, and a shield 118. The coil component 110 is mounted on the substrate 120 by joining the external electrodes 116 and 117 to the land portions 121 and 122, for example, by soldering.

[0024] When viewed in the H direction, the area of ​​each of the land portions 121, 122 is 1.6 times or less the area of ​​each of the external electrodes 116, 117. More preferably, when viewed in the H direction, the area of ​​each of the land portions 121, 122 is 1.3 times or less the area of ​​each of the external electrodes 116, 117. In this embodiment, an input side land portion 121 and an output side land portion 122 are provided, and for example, a signal is input from the input side land portion 121 to the coil component 110 and output from the coil component 110 to the output side land portion 122. Also, in this embodiment, an input side external electrode 116 and an output side external electrode 117 are provided. The input side external electrode 116 is joined to the input side land portion 121, and the output side external electrode 117 is joined to the output side land portion 122.

[0025] The coil component 110 may be, for example, an inductor, or may be used as a filter, a common mode choke coil, a transformer, or a composite component. The coil component 110 may also be used in, for example, a DC-DC converter circuit. By using the coil component 110 with the shield 118, a current characteristic with less noise can be obtained.

[0026] <Coil component structure> The magnetic base 111 is made of a magnetic material. For example, ferrite or a soft magnetic alloy material is used as the magnetic material for the magnetic base 111. Examples of ferrite include Ni-Zn-based, Mn-Zn-based, and these containing Cu. The magnetic material for the magnetic base 111 may be any of various crystalline or amorphous magnetic alloy materials, or may be a combination of a crystalline material and an amorphous material.

[0027] A crystalline alloy magnetic material that can be used as the magnetic material for the magnetic base 111 is, for example, a crystalline alloy material that contains Fe as a main component and one or more elements of Si, Al, Cr, Ni, Ti, and Zr. An amorphous alloy magnetic material that can be used as the magnetic material for the magnetic base 111 is, for example, an amorphous alloy material that contains at least one of B and C in addition to any one of Si, Al, Cr, Ni, Ti, and Zr.

[0028] Pure iron consisting of Fe and unavoidable impurities may be used as the magnetic material for the magnetic substrate 111. A material in which pure iron consisting of Fe and unavoidable impurities is combined with various crystalline or amorphous alloy magnetic materials may be used as the magnetic material for the magnetic substrate 111.

[0029] The magnetic base 111 may include a plurality of metal magnetic particles and a resin portion provided in the gaps between the plurality of metal magnetic particles. As the metal magnetic particles, FeSiCr, FeSiAl, FeSiCrB, Fe-Ni, Fe, etc., which are mainly composed of Fe or Ni, may be used. Alternatively, a combination of these may be used as the metal magnetic particles, and the metal magnetic particles may include, for example, Si, Bi, etc.

[0030] The magnetic base 111 may be made of a composite magnetic material containing a plurality of metal magnetic particles and a binder resin. The binder resin bonds the plurality of metal magnetic particles together. The binder resin is, for example, a thermosetting resin with excellent insulating properties. The magnetic base 111 may be a compact in which the metal magnetic particles are bonded together without the binder resin. The material of the magnetic base 111 is not limited to those explicitly stated in this specification, and any material known as a material for a magnetic base may be used.

[0031] The magnetic base 111 has an outer shape of a rectangular parallelepiped, for example. That is, the magnetic base 111 has an upper surface 131 at one end in the height direction H, and a lower surface 132 at the other end in the height direction H. In addition, the magnetic base 111 has side surfaces 133 at both ends in the length direction L and both ends in the width direction W. The internal conductor 112 is made of a metal material having excellent electrical conductivity. For example, one or more of Cu, Al, Ni, and Ag, or an alloy containing any of these metals, may be used as the metal material for the internal conductor 112. The internal conductor 112 may be a wound metal conductor with an insulating film on its surface, or may be formed on the surface of a substrate, sheet, or the like by plating or printing.

[0032] The internal conductor 112 of this embodiment has a winding portion 113 that winds one or more times. The number of turns of the winding portion 113 is, for example, 1.5 turns or more and 10.5 turns or less. The shape of the winding portion 113 may be planar or spiral. The winding portion 113 may have, for example, two turns facing each other at the upper and lower sides to form one assembly. The internal conductor 112 is manufactured by any of the processes of winding, thin film, and lamination, and is not particularly limited.

[0033] 1 illustrates a so-called horizontally wound turn 113 that turns along the LW plane. The inner conductor 112 may have a so-called vertically wound turn that turns perpendicularly to the LW plane. The internal conductor 112 has lead portions 114, 115 on the lower surface 132 side of the magnetic base 111 for electrical conduction with the outside. In other words, the lead portions 114, 115 connect the external electrodes 116, 117 to the internal conductor 112. The input-side lead portion 114 is connected to, for example, one end on the inner periphery side of both ends of the winding portion 113, and the output-side lead portion 115 is connected to, for example, one end on the outer periphery side of the winding portion 113. The input-side lead portion 114 is connected to the input-side external electrode 116, and the output-side lead portion 115 is connected to the output-side external electrode 117.

[0034] The coil component 110 includes two external electrodes 116, 117 on, for example, the lower surface 132 of the magnetic base 111. Each of the external electrodes 116, 117 has a metal layer made of one or more metals selected from Ag, Cu, Ti, Ni, and Sn. The metal layer is, for example, a layer having a thickness of 1 to 5 μm. Each of the external electrodes 116, 117 may be a combination of a plurality of metal layers, with a total thickness of, for example, 5 to 10 μm. Each of the external electrodes 116, 117 may also be a combination of a metal layer partially containing resin, with a total thickness of, for example, 10 to 20 μm. Each of the external electrodes 116, 117 may have Ni and Sn layers stacked on the surface by plating or the like.

[0035] The external electrodes 116, 117 are made of a metal material with excellent conductivity, similar to the internal conductor 112. The external electrodes 116, 117 are made of one or both of a layer having the same component as the internal conductor 112 and a layer having a component with a higher resistance than the internal conductor 112. The external electrodes 116, 117 are also made of one or both of a layer having the same filling rate as the internal conductor 112 and a layer having a lower filling rate than the internal conductor 112.

[0036] In this embodiment, the external electrodes 116, 117 are provided on the lower surface 132 of the magnetic base 111. As shown in Fig. 1 and other figures, the external electrodes 116, 117 may be provided so that their surfaces are flush with the outer surface (e.g., the lower surface 132) of the magnetic base 111. Alternatively, the external electrodes 116, 117 may be provided so that their surfaces protrude from the outer surface of the magnetic base 111. Note that "provided on a surface" means provided at a location that is visible when the surface is viewed, and does not matter if the surface of the object to be installed is uneven with respect to the installation surface. That is, the surface of the object to be installed may be provided so as to protrude outward from the installation surface, or may be provided so as to be recessed inward from the installation surface. Furthermore, the term "provided on a surface" also applies when a thin layer is interposed between the installation surface and the object to be installed.

[0037] <Shield structure> The shield 118 is conductive and is provided on one or more of the outer surfaces of the magnetic base 111. The shield 118 is connected to the output-side external electrode 117, thereby making it possible to reduce the influence of noise, as will be described later. The shield 118 is not connected to the input-side external electrode 116, and there is no other shield connected to the input-side external electrode 116.

[0038] As an example, the shield 118 is provided on the upper surface 131 of the magnetic base 111, and covers, for example, 10% or more of the area of ​​the upper surface 131. In the case of the first embodiment, the shield 118 has an upper surface portion 118a that covers the entire upper surface 131, and a side surface portion 118b that covers part of the side surface 133. Providing the upper surface portion 118a that covers the entire upper surface 131 provides a high ability to reduce noise. It is desirable for the upper surface portion 118a to cover 90% or more of the area of ​​the upper surface 131.

[0039] The shield 118 is provided between the outer surface of the magnetic base 111 and an insulator (not shown) between the shield 118 and the outer surface of the magnetic base 111. The thickness of the insulator is smaller than the thickness of the shield. If the resistance of the outer surface of the magnetic base 111 is sufficiently high, the insulator is not necessary. The sum of the area of ​​the shield 118 and the area of ​​the output-side external electrode 117 is larger than the area of ​​the input-side external electrode 116. From the viewpoint of noise mitigation, the area of ​​the shield 118 is desirably larger than the area of ​​each of the external electrodes 116, 117. The area of ​​the shield 118 is desirably larger than the combined area of ​​the external electrodes 116, 117.

[0040] The material of the shield 118 may be a metal such as Cu, Al, Ni, or Fe, or an alloy, or may be a resin material containing a metal. As an example, the shield 118 has a higher resistance than the external electrodes 116, 117, and when the external electrodes 116, 117 have portions (layers) with different resistances, the shield 118 has a higher resistance than the portions of the external electrodes 116, 117 with lower resistances. For example, when the materials of the external electrodes 116, 117 are Cu or Ag, the material of the shield 118 is Al or Fe. The shield 118 also has a higher resistance than the internal conductor 112. While providing the shield 118 reduces noise, eddy currents may occur when magnetic flux leaks outward from the magnetic base 111 and passes through the shield 118, and so it is necessary to reduce the eddy currents. For example, as described above, the shield 118 has a higher resistance than the external electrodes 116, 117 and the internal conductor 112, thereby reducing the eddy currents.

[0041] Also, as an example, the shield 118 has a lower resistance than the external electrodes 116, 117, and when the external electrodes 116, 117 have portions (layers) with different resistances, the shield 118 has a resistance equal to or lower than the low-resistance portions of the external electrodes 116, 117. For example, low-resistance materials include Cu and Ag, and the external electrodes 116, 117 and the shield 118 each contain the same components.

[0042] The shield 118 may be magnetic or non-magnetic, but is preferably non-magnetic from the viewpoint of reducing eddy currents. The thickness of the shield 118 is, for example, greater than 1 μm and less than 1 mm. The thickness of the shield 118 is, for example, equal to or less than the thickness of the output electrode. Also, the thickness of the shield is, for example, equal to or less than half the thickness of the output electrode. Also, the thickness of the shield 118 is smaller than the thickness of the external electrodes 116 and 117, thereby reducing eddy currents. In order to further reduce eddy currents, it is preferable that the shield 118 is formed to have a small area and a small thickness in portions other than the upper surface portion 118a (for example, the side surface portion 118b).

[0043] The external electrodes 116, 117 also need to reduce eddy currents, and it is preferable that the areas of the external electrodes 116, 117 are small. For this reason, it is desirable that the area of ​​the external electrodes 116, 117 required for mounting the coil component 110 is secured on the lower surface 132, and that the areas of the external electrodes 116, 117 are small on surfaces other than the lower surface 132. For example, in the first embodiment, the external electrodes 116, 117 are provided only on the lower surface 132, and do not extend to the side surface 133 and the upper surface 132.

[0044] The shield 118 may be formed by machining a metal plate, or by printing, transferring, spraying, or the like of a metal material. In a method of forming the shield 118 by machining, a metal plate is cut and incorporated into the magnetic base 111, or fixed to the magnetic base 111 by adhesion. In a method of forming the shield 118 by printing, transferring, spraying, or the like, a mixed material is prepared by mixing a metal material with a resin or the like, and the mixed material is applied to the outer surface of the magnetic base 111 or the surface of an insulator by the respective method. In addition, a layer of another metal material may be provided on the surface of the shield 118 by plating, or the like.

[0045] <Comparative Example> 4 to 6 are diagrams showing a coil component of a comparative example. Fig. 4 shows a cross-sectional view, Fig. 5 shows a perspective view of the upper surface side, and Fig. 6 shows a perspective view of the lower surface side. Like the coil component 110 of the first embodiment, the coil component 200 of the comparative example includes a magnetic base 210, an internal conductor 220, an external electrode 230, and a shield 240.

[0046] In the comparative example, the external electrode 230 is also provided on the lower surface 212 of the magnetic base 210 and connected to the internal conductor 220. The shield 240 is provided on the upper surface 211 and the side surface 213 of the magnetic base 210, and further extends to a part of the lower surface 212. In the comparative example, the shield 240 is not connected to the external electrode 230, and the shield 240 is connected to the ground via a ground pattern provided on the board separately from the land portion on which the external electrode 230 is mounted. Although the connection lines and the like for connecting the shield 240 to the ground pattern are not shown in the figure, in reality, a space is required for providing the connection lines and the like. For this reason, the coil component 200 of the comparative example is more difficult to miniaturize than the coil component 110 of the first embodiment, and the mounting area is also larger.

[0047] <Noise suppression effect> The effect of noise suppression by the shield will be described below with reference to the measurement results of the far electromagnetic field and the near electromagnetic field.

[0048] FIG. 7 is a graph of the far electromagnetic field in a coil component without a shield, FIG. 8 is a graph of the far electromagnetic field in the coil component of the first embodiment, and FIG. 9 is a graph of the far electromagnetic field in the coil component of the first embodiment when there is no connection between the shield and the external electrode.

[0049] In the graphs of Figures 7 to 9, the horizontal axis indicates frequency, and the vertical axis indicates electromagnetic field strength. The electromagnetic field was measured with the coil components arranged so that the LW plane was the horizontal plane, and measurements were made using an antenna in the vertical direction and an antenna in the horizontal direction. In the graphs of Figures 7 to 9, the vertical measurement results are shown with thick lines, and the horizontal measurement results are shown with thin lines.

[0050] As shown in Fig. 7, in the coil component not provided with a shield, large noise occurs in both the vertical and horizontal directions. In contrast, as shown in Fig. 8, it can be seen that noise is suppressed in the case of the coil component 110 of the first embodiment. It has also been confirmed that the noise suppression effect shown in Fig. 8 is equivalent to the noise suppression effect of the coil component 200 of the comparative example shown in Figs. 4 to 6. Note that in the coil component 110 of the first embodiment, when the connection between the shield 118 and the external electrode 117 on the output side is cut off, the noise suppression effect cannot be obtained, as shown in Fig. 9.

[0051] It is believed that because the current change is cancelled out on the output side of coil component 110 of the first embodiment, the electromagnetic field of noise is suppressed by shield 118. That is, in coil component 110 of the first embodiment, it is not necessary to connect shield 118 to ground, and the noise suppression effect of shield 118 is sufficiently obtained. Therefore, electrodes and patterns on the board required for connecting shield 118 to ground are not required, which contributes to miniaturization of coil component 110 and reduction of the mounting area.

[0052] For example, when viewed from the top surface 131, the difference between the external area of ​​the maximum part of coil component 110, including shield 118 and external electrodes 116, 117, and the external area of ​​magnetic base 111 is within 5%. Furthermore, when mounting coil component 110 on substrate 120, a mounting method can be adopted in which the area of ​​the substrate attachment is smaller than the area of ​​coil component 110. In other words, since no connection to ground is required, the range of mounting coil component 110 to the substrate can be accommodated within the external dimensions of coil component 110.

[0053] Specifically, the coil component 110 is, for example, 4 mm 3 The coil component 110 can be realized in a smaller volume. Also, the area required for mounting the coil component 110 on a substrate is, for example, 4 mm 2 In this way, the coil component 110 is miniaturized, the mounting area on the substrate 120 is reduced, and the distance to other components can be reduced due to noise suppression, so that a large number of components can be effectively mounted on the substrate 120.

[0054] FIG. 10 is a diagram showing a schematic diagram of a measurement environment of a near electromagnetic field. 10 is the X direction and the Y direction is the upward direction, in a measurement region R including the coil component 110 mounted on the substrate 120. Since the X direction corresponds to the -L direction and the Y direction corresponds to the -W direction, the input side land portion 121 is located in the -X direction with respect to the coil component 110, and the output side land portion 122 is located in the +X direction with respect to the coil component 110.

[0055] The circuit board 100 is provided with a switch semiconductor 123 as an element for inputting a signal to the coil component 110, and also with other elements 124. Fig. 11 and Fig. 12 are graphs showing the measurement results of the near magnetic field in a coil component without a shield. Fig. 11 shows a three-dimensional graph of the measurement results in the measurement region R, and Fig. 12 shows a graph of the measurement results at each point crossing the center of the coil component in the X direction.

[0056] Fig. 13 and Fig. 14 are graphs showing the measurement results of the near magnetic field in the coil component 110 of the first embodiment. Fig. 13 shows a three-dimensional graph of the measurement results in the measurement region R, and Fig. 14 shows a graph of the measurement results at each point crossing the center of the coil component 110 in the X direction.

[0057] In each of the three-dimensional graphs in FIG. 11 and FIG. 13, the positions of the coil components are shown in rectangular frames on the XY plane. As shown in Figures 11 and 12, in the case of a coil component without a shield, a strong magnetic field is generated directly above the coil component. In contrast, as shown in Figures 13 and 14, in the case of the coil component 110 of the first embodiment, the strength of the magnetic field directly above the coil component 110 is lower than the surrounding area, and it is clear that the magnetic field is strongly suppressed by the shield 118.

[0058] Fig. 15 and Fig. 16 are graphs showing the measurement results of the near electric field in a coil component without a shield. Fig. 15 shows a three-dimensional graph of the measurement results in the measurement region R, and Fig. 16 shows a graph of the measurement results at each point crossing the center of the coil component in the X direction.

[0059] Fig. 17 and Fig. 18 are graphs showing the measurement results of the near electric field in the coil component 110 of the first embodiment. Fig. 17 shows a three-dimensional graph of the measurement results in the measurement region R, and Fig. 18 shows a graph of the measurement results at each point crossing the center of the coil component 110 in the X direction.

[0060] In each of the three-dimensional graphs in FIG. 15 and FIG. 17, the positions of the coil components are shown in rectangular frames on the XY plane. As shown in Figures 15 and 16, in the coil component without a shield, strong measurement values ​​were obtained directly above the coil component in the case of the electric field as in the case of the magnetic field. In contrast, as shown in Figures 17 and 18, in the case of the coil component 110 of the first embodiment, the electric field is suppressed, and the suppression effect is particularly noticeable on the output side.

[0061] In this way, the effect of suppressing noise in the coil device 110 of the first embodiment was confirmed also from the measurement of the near electromagnetic field. A typical example where noise suppression effects confirmed by measurements of far and near electromagnetic fields are found is a DC-DC converter. The output side of the circuit in which the coil component is used is designed to have low impedance over a wide frequency band corresponding to the switching frequency, and in such cases, the output side of the coil component has the same function as ground, so noise suppression effects can be achieved. For example, the switching frequency is 1 MHz or higher and 10 MHz or lower. <Other embodiments> Next, another embodiment will be described. In the following, the differences from the first embodiment will be focused on, and overlapping descriptions will be omitted.

[0062] Fig. 19 to Fig. 21 are diagrams showing a coil device according to the second embodiment, in which Fig. 19 shows a cross-sectional view, Fig. 20 shows a perspective view of the upper surface side, and Fig. 21 shows a perspective view of the lower surface side. Similar to the coil component 110 of the first embodiment, the coil component 300 of the second embodiment includes a magnetic base 111, an internal conductor 112, an input-side external electrode 116, an output-side external electrode 117, and a shield 118. The shield 118 has an upper surface portion 118a and a side surface portion 118b, but in the second embodiment, the side surface portion 118b is minimized and is provided on only one of the side surfaces 133 in order to connect the shield 118 and the output-side external electrode 117.

[0063] That is, in the coil component 300 of the second embodiment, the main portion of the shield 118 extends over two of the six outer surfaces (upper surface 131, lower surface 132, and four side surfaces 133) of the magnetic base 111. Magnetic flux leaking outward from the magnetic base 111 is often biased in a specific direction. In the coil component 300 of the second embodiment, for example, the leakage of magnetic flux is biased in the width direction W, and the shield 118 is provided so as to avoid the side surfaces 133 facing the width direction W, thereby suppressing the generation of eddy currents.

[0064] Furthermore, in the coil component 300 of the second embodiment, the areas of the external electrodes 116, 117 are smaller than those of the coil component 110 of the first embodiment, and eddy currents are also suppressed in the external electrodes 116, 117. Furthermore, in the coil component 300 of the second embodiment, the external electrodes 116, 117 do not reach the side surface 133. Therefore, the external electrodes 116, 117 do not affect the outer dimensions of the coil component 300 in the direction of the side surface 133, and the coil component 300 can be further miniaturized.

[0065] Fig. 22 to Fig. 24 are diagrams showing a coil device according to a third embodiment, in which Fig. 22 shows a cross-sectional view, Fig. 23 shows a perspective view of the upper surface side, and Fig. 24 shows a perspective view of the lower surface side. The coil device 400 of the third embodiment also includes a magnetic base 111, an internal conductor 112, an input-side external electrode 116, an output-side external electrode 117, and a shield 118.

[0066] In the third embodiment, the shield 118 has a protruding portion 118c in addition to the top surface portion 118a and the side surface portion 118b. The protruding portion 118c extends from the top surface portion 118a and spreads outward, protruding from the magnetic base 111. That is, when viewed in the -H direction toward the top surface 131, the protruding portion 118c of the shield 118 spreads outward beyond the top surface 131. Such protruding portion 118c can reduce the intrusion of the electromagnetic field (noise) from the side surface 133 where the shield 118 is not provided, and can suppress an increase in eddy currents generated in the shield 118.

[0067] In the third embodiment, the protruding portion 118c protrudes in three directions (+L direction, +W direction, -W direction) from the upper surface 131, but the protruding portion 118c may protrude in only one direction from the upper surface 131, may protrude in two directions, or may protrude in four directions (+L direction, -L direction, +W direction, -W direction). When protruding in two directions, the two directions may be opposite to each other, or may be two directions that intersect each other.

[0068] As a method for forming the shield 118 having the protruding portion 118c, for example, a method of attaching a metal plate to the upper surface 131 of the magnetic base 111 can be considered. Fig. 25 to Fig. 27 are diagrams showing a coil device according to a fourth embodiment, in which Fig. 25 shows a cross-sectional view, Fig. 26 shows a perspective view of the output side, and Fig. 27 shows a perspective view of the input side.

[0069] The coil device 500 of the fourth embodiment includes a magnetic base 111, an internal conductor 112, an input-side external electrode 116, an output-side external electrode 117, and a shield 118, as well as an insulating layer 510 and a mark 520. In the coil component 500 of the fourth embodiment, so-called two-surface electrodes extending from the lower surface 132 to the side surface 133 are provided as the external electrodes 116, 117. Furthermore, the lead portions 114, 115 of the internal conductor 112 extend toward the side surface 133 of the magnetic base 111 and are connected to the external electrodes 116, 117 on the side surface 133 side.

[0070] In the case of a two-surface electrode, a noise electromagnetic field is likely to be generated from a portion of the input-side external electrode 116 that extends to the side surface 133. For this reason, in the coil component 500 of the fourth embodiment, the side surface portion 118b of the shield 118 reaches the input side of the coil component 500 and covers the input-side external electrode 116. Also, in order to maintain insulation between the input-side external electrode 116 and the shield 118, an insulating layer 510 is provided between the external electrode 116 and the shield 118.

[0071] Such a shield 118 suppresses noise even in the coil component 500 having the external electrodes 116 and 117 that are two-surface electrodes. Mark 520 is a display unit that indicates the input side of coil component 500. Symbols, characters, or the like other than mark 520 may be used as the display unit that indicates the input side of coil component 500. Providing a display unit such as mark 520 makes it easy to identify the input side of coil component 500, thereby preventing the coil component from being mounted in the wrong direction.

[0072] FIG. 28 is a cross-sectional view showing a coil component according to the fifth embodiment. The coil device 600 of the fifth embodiment includes a magnetic base 111, an internal conductor 112, an input-side external electrode 116, an output-side external electrode 117, a shield 118, and an insulating layer 510.

[0073] In the coil device 600 of the fifth embodiment, the insulating layer 510 is provided over a wide area inside the shield 118. The insulating layer 510 covers multiple surfaces (e.g., the top surface 131 and two or more side surfaces 133) of the magnetic base 111, and may be provided over the entire inside of the shield 118. The insulating layer 510 creates a distance between the shield 118 and the magnetic base 111, thereby reducing eddy currents. The insulating layer 510 may also serve as an adhesive layer that fixes the shield 118 to the magnetic base 111. [Explanation of symbols]

[0074] 100 Circuit Board 110, 200, 300, 400, 500 Coil parts 111 Magnetic substrate 112 Inner conductor 113 Orbiting Club 114, 115 Drawer section 116, 117 External electrode 118 Shield 118a Top part 118b Side part 118c overhang part 120 Substrate 121, 122 Land Department 131 Top surface 132 Bottom surface 133 Side 510 Insulating layer 520 marks

Claims

1. A magnetic substrate having magnetism; a conductor provided on a part of the magnetic base; an input electrode provided on an outer surface of the magnetic base and connected to one end of the input side of the conductor; an output electrode provided on an outer surface of the magnetic base and connected to one end of the output side of the conductor; a conductive shield provided on an outer surface of the magnetic base, connected to the output electrode of the input electrode and the output electrode, the total area of ​​which including the output electrode is larger than the area of ​​the input electrode; A coil component comprising:

2. the magnetic base has a first surface on which the input electrode and the output electrode are provided, a second surface facing the opposite side to the first surface, and a side surface connecting the first surface and the second surface, The coil component according to claim 1 , wherein the shield has a second surface portion provided on the second surface and a side surface portion provided on the side surface.

3. The coil component according to claim 2 , wherein the area of ​​the second surface portion of the shield is greater than the total area of ​​the side surface portions.

4. The coil component according to claim 2 , wherein the second surface portion of the shield covers 90% or more of the second surface.

5. The coil component according to claim 4 , wherein the shield has a protruding portion that is positioned outward from the second surface when viewed toward the second surface.

6. The coil component according to claim 1 , wherein the thickness of the second surface portion of the shield is equal to or smaller than the thickness of the output electrode.

7. The coil component according to claim 1 , wherein the shield contains a material having a higher resistance than the output electrode.

8. The coil component according to claim 1 , wherein the shield is made of a non-magnetic metal.

9. The coil component according to claim 2 , wherein the input electrode and the output electrode are spaced apart from the side surface.

10. 2. The coil component according to claim 1, further comprising markings for identifying an input side and an output side of the conductor.

Images